The differential diagnosis of intrascrotal pathology includes a myriad of benign and malignant entities. Timely detection is imperative to reduce the morbidity associated with many of these disease processes.
Inflammatory intrascrotal disorders (eg, epididymitis, orchitis, and testicular or appendiceal torsion) are rarely fatal but can lead to sepsis, testicular loss, and decreased fertility if treatment is delayed. Similarly, diagnosis of testicular cancer when it is organ-confined lessens the morbidity associated with disease progression and attendant treatments.
Patients who present with intrascrotal pathology usually-but not always-have subjective complaints. Most inflammatory lesions produce scrotal and/or groin discomfort and pain. Patients with associated urinary tract or urethral infections often complain of dysuria or urethral pain. Some patients, however, offer no complaint and present with an asymptomatic intrascrotal mass that is either self-discovered or palpated by a physician during the course of a routine physical examination.
When you evaluate a patient with intrascrotal pathology, one of the most important clinical determinations is, "Is the lesion malignant or inflammatory?" In this article, we sort through the differential diagnosis and highlight the key findings in the physical, laboratory, and radiographic examinations.
DIFFERENTIAL DIAGNOSIS OF TESTICULAR PATHOLOGY
Testicular cancer. Most patients who have testicular cancer present with a painless mass within the testis (Case 1). Some patients may complain of a sensation of "heaviness" in the affected testis. Testicular tenderness is rare unless there has been necrosis or hemorrhage within the tumor, which is particularly unusual in patients who have a pure seminoma.1
The mass is usually readily palpable and is commonly firmer than the remainder of the testis. Palpation reveals a normal epididymis posterior to the testis. In patients who have disseminated disease, retroperitoneal and/or supraclavicular adenopathy may occasionally be found.
Scrotal sonography often confirms the diagnosis (Table).2 Most testicular tumors are distinguished by their heterogeneous characteristics compared with normal tissue (Figure 1).
The serum alpha-fetoprotein (AFP) level is elevated in virtually all patients with testicular embryonal carcinoma and in some patients with nonseminomatous or mixed germ cell tumors. The serum level of β subunit of human chorionic gonadotropin (β-hCG) may be elevated in a small percentage of patients with seminomas and in some patients with mixed germ cell tumors. The lactate dehydrogenase (LDH) level may be somewhat elevated in patients with testicular cancer.3
Primary testicular cancer is more common than secondary testicular cancer, which can occur in patients with lymphoma or leukemia and rarely in those with prostate cancer or melanoma. A cryptorchid, or undescended, testis has a much greater lifetime risk of malignant transformation than does a descended testis.
Other testicular and paratesticular tumors. Non-germ cell testicular tumors, such as Sertoli cell tumors, Leydig cell tumors, and gonadoblastomas, occur infrequently and are difficult to distinguish from the more common malignant tumors.Paratesticular (spermatic cord) sarcomas are uncommon, but they are included in the differential diagnosis if a firm lesion is palpably outside the testis and epididymis.
Orchitis. Patients who have orchitis present with testicular pain and often have ipsilateral swelling and tenderness. The inflammation is usually unilateral and frequently secondary to the mumps and Coxsackievirus infections.
DIFFERENTIAL DIAGNOSIS OF NONTESTICULAR INTRASCROTAL PATHOLOGY
Epididymitis. Patients usually present with intrascrotal and/or groin pain or discomfort (Case 2). In this setting, groin discomfort occurs because the innervation of the epididymis is via the intermediate and inferior spermatic nerves, which originate from the hypogastric and pelvis plexus, respectively. Palpation typically reveals tenderness within the epididymis and a normal testis that is distinct from the epididymis.
Epididymitis can be acute or chronic, noninfectious or infectious. Noninfectious acute epididymitis is more common than infectious acute epididymitis and is considered idiopathic. Chronic epididymitis is rarely infectious (except for cases caused by Mycobacterium tuberculosis); patients usually present with chronic pain and tenderness in the epididymis. One unproven but time-honored theory (Graves theory) postulates that "straining" forces sterile urine down the vas deferens and into the epididymis, which creates an attendant inflammatory response.4
In patients with infectious epididymitis, the most common causative organisms are:
Chlamydia trachomatis and Neisseria gonorrhoeae in heterosexual men aged 35 years and younger.
Coliforms in older men and in homosexual men who engage in anal intercourse.
Viruses, M tuberculosis, and Cryptococcus and Brucella organisms are less common causes of infection. Patients may have dysuria and pyuria, which is secondary to the inflammatory response associated with infection. Although pyuria may aid in the diagnosis of epididymitis, its presence does not rule out either torsion or testicular neoplasia.
Urinalysis, urine cultures, urethral swab cultures, and Gram staining can be useful in the evaluation. White blood cells in the urine suggest inflammation, which is usually associated with infection in patients with epididymitis. Gram staining of a urethral swab specimen or centrifuged urinary sediment may demonstrate the characteristic intracellular "coffee bean" diplococci in patients with N gonorrhoeae infection. In patients with C trachomatis infection, the urethral culture or a DNA probe may be positive.5 In those with coliform infections, the urine culture is often confirmatory.
Epididymal cysts. Patients who have an epididymal cyst, or spermatocele, present with an asymptomatic intrascrotal mass that is usually located in the caput of the epididymis. Epididymal cysts represent dilatation of epididymal tubules with seminal fluid components.
Adenomatoid tumor of the epididymis. This uncommon benign solid tumor is often difficult to distinguish from chronic epididymitis.
Testicular torsion. Although it is most common in prepubertal boys (Case 3), testicular torsion may occur at any age. A predisposition is an anatomic congenital "bell-clapper" configuration of the spermatic cord and tunica vaginalis.
Pain results from testicular ischemia. Typically, the affected testis is high-riding and lies horizontally in the scrotum, compared with the contralateral testis. The serum LDH level is often markedly elevated.
Doppler imaging and radionuclide scanning can help confirm the diagnosis of testicular torsion. In an ultrasonic Doppler flow probe study, the contralateral testis serves as the control, and an absent pulse on the affected side is virtually confirmatory. Nuclear scanning demonstrates the presence or absence of blood flow to the affected testis (Figure 2).
Appendiceal torsion. There are two appendices, or vestigial remnants, in the scrotum: the appendix testis and the appendix epididymis. Either can undergo torsion. Appendiceal torsion is most common in young boys, but it can also occur in older males.
Patients usually present with ipsilateral scrotal pain and point tenderness over the torted appendix. In a light-colored scrotum, an area of infarction and inflammatory reaction-the characteristic "blue dot" sign-can often be seen.6 Ultrasonography can be helpful in identifying torted appendices (Figure 3).
Hydroceles. These result from collection of peritoneal-like fluid within the tunica vaginalis of the spermatic cord. Patients usually present with a painless enlarged scrotum, and the hydrocele often can be readily transilluminated. Occasionally, a "reactive" hydrocele can form in patients who have epididymitis, but in this setting, pain and discomfort are present.
Varicoceles. These represent dilated veins of the pampiniform plexus. Patients usually have no symptoms. Rarely, a patient may complain of heaviness or scrotal discomfort secondary to venous engorgement in the upright position. A characteristic "bag of worms" may be palpable when the patient is standing.
Varicoceles are far more common on the left side; if there is a right-sided varicocele, a left-sided one is almost always present as well. A varicocele detumesces when the patient is prone. If the varicocele does not detumesce when the patient assumes the supine position or if there is an isolated right-sided varicocele, suspect an upstream spermatic vein occlusion, such as a thrombus or tumor in the renal vein or inferior vena cava.
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